TLC assay

A particular protocol for TLC assay describes its staining reagents as 1% aq KMnO4 and a mixture of p-anisaldehyde and sulfuric acid in 1:1 methanol-water. The mobile phase used was 1:4 ethyl acetate-hexane. Can anybody explain how to use a mixture of p-anisaldehyde and sulfuric acid in 1:1 methanol-water ? What is the purpose of using this? for staining or what? Is that sprayed on the TLC plate after running in the solvent ? how to interpret ?